JPH05239490A - Purification of hydraulic oil, and filter circuit used therefor - Google Patents

Abstract

PURPOSE:To provide a method for purifying a hydraulic oil, which makes it possible to convert impurities dissolved in a hydraulic oil into a solid material for easy removal without using any chemical adsorption filter whose maintenance is troublesome, and to provide a filter circuit. CONSTITUTION:This method for purifying a hydraulic oil comprises the first processing step for introducing a hydraulic oil bypassed from an oil supply line 3 on the side of hydraulic device into a processing tank 9 to dilute in with a solvent, causing the impurities dissolved in the oil to deposit as a solid material in the liquid, the second processing step for passing the diluted hydraulic oil through a filter 10 to remove the solid impurities present in the diluted liquid, and the third processing step for sending the diluted liquid filtrated through the filter into distillation device 11 to effect distillation to thereby separate into a hydraulic oil and a solvent, wherein the hydraulic oil purified through the consecutive processing steps is returned to the oil supply line while the solvent evaporated in the distillation device is condensed by a subsequent condenser 12 and the returned to the processing tank for reuse.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a purification method for removing impurities produced in and mixed with a phosphate ester hydraulic oil used in a high-pressure hydraulic system, and a filter circuit therefor.

[0002]

2. Description of the Related Art In a high-pressure hydraulic system such as an electro-hydraulic governor of a steam turbine, a phosphate ester type hydraulic system which is excellent in anti-ignition property as a hydraulic fluid from the viewpoint of fire prevention and has little property change under high temperature and high pressure. Oil is widely used. By the way, in such a phosphate ester type hydraulic fluid, the phosphate ester is deteriorated and decomposed due to mixing of moisture from the surroundings during use, temperature rise, etc., and impurities (acids and corrosion due to acid, A dissolved product) will be produced.

Therefore, conventionally, a hydraulic system is combined with a filter circuit as shown in FIG. 3, and hydraulic oil bypassed from the hydraulic system side is guided to the filter circuit to be converted into hydraulic oil together with solid foreign matters such as metal powder and packing scraps. Remove the dissolved impurities. In the figure, 1 is a hydraulic oil tank, 2 is an oil supply line piped between the hydraulic oil tank 1 and a hydraulic device 3, 4 is a hydraulic pump, 5 is a filter circuit, and the filter circuit 5 is a chemical adsorption filter 6 , A mechanical filter 7 and a circulation pump 8.

With this structure, the hydraulic oil bypassed from the oil supply line 3 is flowed into the filter circuit 5, whereby the adsorption filter 5 removes impurities dissolved in the oil, and the filter 6 removes the hydraulic oil. The filtered hydraulic oil removes solid impurities such as metal powder and packing scraps, and the purified hydraulic oil is returned to the oil supply line 2 again.

[0005]

By the way, in order to chemically adsorb and remove the impurities dissolved in the phosphate ester hydraulic oil, the adsorption conditions are complicated and it is difficult to always maintain a stable capacity. In addition, it is necessary to replace the adsorption filter frequently because the adsorption capacity deteriorates with use, and a large amount of waste is generated with the replacement of the filter. Is desired.

The present invention has been made in view of the above points, and an object thereof is to solve the above problems and to eliminate impurities dissolved in hydraulic fluid without using a chemical adsorption filter which is troublesome to maintain. (EN) It is intended to provide a method for purifying hydraulic oil, which can be easily removed by converting solids into solid matter, and a filter circuit.

[0007]

According to the purification method of the present invention, the above-mentioned object is to dilute the hydraulic oil bypassed from the oil supply line of the hydraulic system with a solvent and to precipitate impurities dissolved in the oil as solid matter. The first treatment step is performed, and the second treatment step is performed in which the diluent for the hydraulic oil is passed through a filter to remove solid contaminants. The diluent for the hydraulic oil filtered by the filter is distilled to separate the hydraulic oil and the solvent. Has a third process step of separating,
This is achieved by returning the purified hydraulic oil to the oil supply line through the above processing steps in order.

Further, there are the following modes for carrying out the cleaning method. (1) As a solvent, a low molecular weight low boiling point paraffinic solvent is used. (2) In the third treatment step of the above method, the evaporated solvent vapor is condensed and then returned to the first step for reuse. (3) In the third treatment step, the solvent is evaporated by heating distillation or reduced pressure distillation to separate from the hydraulic oil.

On the other hand, according to the present invention, the filter circuit used for carrying out the above-mentioned purification method is designed to inject and dilute the hydraulic oil taken in from the oil supply line of the hydraulic device into the solvent to remove impurities dissolved in the oil. A treatment tank for depositing a solid matter,
A filter connected to the latter stage of the treatment tank to filter the diluting fluid of the hydraulic oil, a distillation device connected to the latter stage of the filter to separate the hydraulic oil and the solvent, and connected between the distillation device and the treatment tank. Then, a condenser for condensing the solvent vapor separated from the hydraulic oil is combined and configured.

Further, as the distilling device in the filter circuit, a heating distilling device or a reduced pressure distilling device can be adopted.

[0011]

By cleaning the phosphate ester hydraulic oil through the above filter circuit, the dissolved impurities generated in the hydraulic oil due to the deterioration of the phosphate ester type are dissolved in the hydraulic fluid in the first treatment step by solvent dilution, Upon cooling, it turns into a solid and begins to precipitate in the liquid. Therefore, in the next second treatment step, the precipitated impurities, together with other solid foreign matters, are removed as solid impurities by filtration through the filter. On the other hand, the mixed liquid of the hydraulic oil from which the impurities have been removed and the solvent is distilled in the subsequent third treatment step, where the solvent having a lower boiling point than the hydraulic oil evaporates and is separated from the hydraulic oil. The oil is returned to the oil supply line of the hydraulic system, and the solvent vapor is condensed and then returned to the first processing step for reuse. By appropriately selecting the type of solvent, the dilution rate, and the treatment temperature in the first treatment step, the purification treatment can be efficiently performed according to the state of impurities generated in the hydraulic oil. Further, by appropriately extracting the non-condensable gas to the outside of the system during the hydraulic oil purification process, it is possible to simultaneously remove water mixed as water vapor.

[0012]

Embodiments of the present invention will be described below with reference to the drawings. In the drawings of the embodiments, the same members as those in FIG. 3 are designated by the same reference numerals. Example 1 In FIG. 1, 9 is a processing tank in which a low molecular weight low boiling point paraffinic solvent (for example, a boiling point of about 40 to 80 degrees) is stored, 10 is a mechanical filter using a filter medium, 1
1 is a heating distillation apparatus, 12 is a condenser for condensing a solvent, 1
Reference numeral 3 is a liquid feed pump, and a hydraulic oil extraction pipe line 14, a hydraulic oil return pipe line 15, and a solvent return pipe line 16 are connected as shown in the drawing between the respective equipments and between the oil supply line 3. It constitutes a device for purifying hydraulic oil. In addition, 11a is a heater of the heating distillation apparatus 11, and 17 is a drain pot.

With such a configuration, when the hydraulic oil bypassed from the supply side pipeline (high pressure side) of the oil supply line 3 is injected into the processing tank 9 through the extraction pipeline 14 during operation of the hydraulic system, the hydraulic oil is converted into solvent in the processing tank. Diluted with. By appropriately adjusting the dilution ratio and cooling temperature in the processing tank 9, the impurities dissolved in the hydraulic fluid are deposited as solids in the hydraulic fluid diluent. Then, the solid matter precipitated in the liquid and other mixed solid foreign matters are sent from the processing tank 9 to the filter 10 in the subsequent stage by the liquid sending pump 13 together with the hydraulic fluid diluting liquid, where the impurities are solid impurities in the filter. Removed by filtration. On the other hand, the diluting liquid of the hydraulic oil filtered by the filter 10 enters the heating / distilling device 11 in the subsequent stage, and the low boiling point solvent is heated and evaporated to be separated from the hydraulic oil. Further, the hydraulic oil separated here is taken out from the distilling device 11 and is returned to the return side pipeline (low pressure side) of the oil supply line 3 via the hydraulic oil return pipeline 15. On the other hand, the solvent vapor evaporated in the distillation apparatus 11 is condensed in the condenser 12 at the subsequent stage, and then sent to the processing tank 9 for reuse.

Example 2 FIG. 2 shows an application example of Example 1 described above. In this example, a vacuum distillation apparatus 18 is incorporated in place of the heating distillation apparatus in FIG. Reference numeral 19 is a hydraulic oil return pump, and 20 is a solvent vapor compressor. The hydraulic oil purifying process with such a configuration is basically performed in the same manner as in the first embodiment.
On the other hand, in the embodiment shown in FIG. 2, the processing tank 9 is pressurized by the compressor 19, and this pressure causes the diluent of hydraulic oil to be sent from the processing tank 9 through the filter 10 to the depressurizing distillation apparatus 18 to evaporate the solvent under reduced pressure. And separate it from hydraulic oil. Further, the hydraulic oil taken out from the distilling device 18 is returned to the oil supply line 3 on the hydraulic device side through the return pipe 15 after the pressure is increased by the return pump 20.

[0015]

As described above, according to the method and apparatus for purifying hydraulic oil of the present invention, impurities dissolved in phosphate ester hydraulic oil can be diluted by diluting the hydraulic oil with a solvent. It can be precipitated as a solid in the liquid, and thus impurities can be easily removed as solid impurities by filtration with a mechanical filter in the subsequent stage. Moreover, since impurities are removed as solids, a stable treatment function can be maintained compared to conventional chemical adsorption filters, and the filter can be used for a long time. The advantages are that maintenance management is easy, such as less is required. Further, the solvent is separated from the hydraulic oil by the distilling device and then condensed and returned to the processing tank for use, so that the consumption amount is small.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a filter circuit according to an embodiment of the present invention.

FIG. 2 is a block diagram of a filter circuit according to an embodiment of the present invention, which is different from FIG.

FIG. 3 is a block diagram of a conventional filter circuit.

[Explanation of symbols]

 1 Hydraulic Oil Tank 3 Oil Supply Line 9 Processing Tank 10 Filter 11 Heating Distillation Device 12 Condenser 18 Decompression Distillation Device

Claims (8)

[Claims] 1. A method of purifying a hydraulic oil, which is produced in a phosphate ester hydraulic oil used in a hydraulic system and removes mixed impurities, wherein the hydraulic oil bypassed from an oil supply line on the hydraulic system side with a solvent. A first treatment step for diluting and precipitating impurities dissolved in oil as a solid matter, a second treatment step for removing a solid contaminant by passing a diluent of hydraulic oil through a filter, and a filtration with a filter And a third treatment step for distilling the diluted fluid of the hydraulic oil to separate the hydraulic oil and the solvent.
A method of purifying hydraulic oil, characterized in that the hydraulic oil purified through the above-mentioned processing steps is returned to the oil supply line. 2. The method for purifying hydraulic oil according to claim 1, wherein the solvent is a low molecular weight low boiling point paraffinic solvent. 3. The method for purifying hydraulic oil according to claim 1, wherein the solvent vapor evaporated in the third treatment step is condensed and returned to the first treatment step for reuse. 4. The method for purifying hydraulic oil according to claim 1, wherein in the third treatment step, the solvent is heated and evaporated by heating distillation to separate the solvent from the hydraulic oil. 5. The method for purifying hydraulic oil according to claim 1, wherein in the third treatment step, the solvent is evaporated under reduced pressure by vacuum distillation to separate the solvent from the hydraulic oil. 6. A treatment tank for injecting hydraulic oil taken in from a refueling line of a hydraulic device into a solvent to dilute it and depositing impurities dissolved in the oil as a solid matter, and a treatment tank connected to the latter stage of the treatment tank. A filter for filtering the diluted fluid of hydraulic oil, a distilling device connected to the latter stage of the filter to separate hydraulic oil and solvent, and a distilling device connected to the processing tank to separate hydraulic oil. A hydraulic oil filter circuit used for carrying out the purification method according to claim 1, wherein a condenser for condensing solvent vapor is combined. 7. A filter circuit for hydraulic oil according to claim 6, wherein the distilling device is a heating distilling device. 8. A filter circuit for hydraulic oil according to claim 6, wherein the distillation device is a vacuum distillation device.